I-FARM is a web-based farming decision tool designed to simulate whole farm interactions among crops, livestock, carbon and nutrient flows, soil erosion, labor and energy requirements, and overall farm profitability.  Recently I-FARM has been expanded to include bioenergy crops and residues, including switchgrass and corn stover.  Once farmers have loaded up the biophysical properties of their farm (currently facilitated by a GIS data-mining tool for Iowa) they can evaluate a wide range of scenarios for different crop rotations, yield, price, etc.  Results for several farming systems will be presented, demonstrating the variation in price and productivity even in highly productive farmland.  Implications for biomass price and policy incentives will be discussed.